Brake for electric motors



Jilly 27, 1954 L. A. DURANT 2,685,043

BRAKE FOR ELECTRIC MOTORS Filed March 22, 1952 Patented July 27, 1954 BRAKE FOR ELECTRIC MOTORS Lyndon A. Durant, Chicago, Ill., assignor to General Patent Corporation, Chicago, 111., a corporation of Illinois Application March 22, 1952, Serial No. 278,080

2 Claims. 1

This invention relates to certain new and useful improvements in motor-driven gears and has as an object the provision of an improved construction of the character hereinafter described which will be highly efficient in use and economical in manufacture.

The present invention constitutes an improvement over that shown in application of Leo Galinslri for United States Letters Patent, Serial No. 278,079, filed on even date hereof.

Specifically the present invention relates to a simple and efficient arrangement for braking the rotation of the rotor of an electric motor and thereby preventing overriding of such rotor by its own inertia.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction, and in which:

Fig. 1 is a perspective view of a motor embodying my invention;

Fig. 2 is an elevational view of one side of the motor;

Fig. 3 is a bottom view showing the rotor attracted to its normal operative position with respect to the stator;

Fig. 4 is an enlarged sectional detail view taken substantially on line 4-4 of Fig. 3; W

Fig. 5 is a sectional detail view taken substantially on line 55 of Fig. l;

Fig. 6 is a view of a disc member embodied in the invention, looking in the direction of line 6-6 of Fig. 4;

Fig. 7 is an end view of the driving gear embodied in the invention;

Fig. 8 is an enlarged elevational View of the driven gear embodied in the invention;

Fig. 9 is a sectional View similar to Fig. 4 but showing a construction in which the driving gear embodied in the invention remains at all times in driving engagement with a driven gear.

In the drawings I have shown a preferred form of construction by which the several objects of my invention are accomplished. In this connection, a mounting plate is indicated at H). By means of such plate the motor I l is mounted to a fixed support. This mounting plate I0 is hollow in construction to provide an enclosure for a train of gears I 2 including a driven gear it, an intermediate gear 14, and a pinion I5, the latter mounted on a work shaft 16. The intermediate gear is operativel connected to the driven gear by a pinion l3. The motor I l comprises a stator I! and a rotor H3. The rotor I8 is mounted on a shaft l9. Such shaft 19 together with its rotor is normally projected laterally with respect to the stator IT by means of a spring 23 arranged between the rotor 18 and the adjacent wall 21 of the mounting plate H) and mounted to embrace a sleeve 22 fixed to the wall 2|.

One end of this rotor shaft I9 is formed to provide a driving gear 23. The corresponding sides 24 of each tooth of this gear 23 are formed substantially triangular in cross section, and the top edges of the gear are preferably flat as at 25. The opposite end portion of the rotor shaft i9 is journaled through a bearing 25 provided by a bracket 21 fixed to the stator I! as at 28.

The teeth of the driven gear [3 at corresponding sides 29 are likewise triangular in cross section, with the apexes extending radially from the long axis of the gear l3. The tops 30 of the teeth of the gear I 3 are semicircular in cross section and merge into parallel adjacent walls 29'. By forming the abutting faces or sides of the teeth of the driving gear 23 and those of the driven gear 13 triangular in cross section, with the apexes extending radially with respect to the long axis of the gears, whenever the gears are moved into meshing relation with respect to each other such gears will be self-aligning so that a proper driving engagement will result, irrespective of whether the teeth of the one gear are out of alignment with the teeth of the other of the gears.

By disengaging the driving gear from the driven gear when the stator of the motor is deenergized, which results in the rotor being moved from the magnetic field of the stator by the spring 20, the work shaft It can be freely and manually rotated when occasion arises.

On one face of the rotor is arranged a disc 3! by pressing against the rotor shaft l9 attaching prongs 32. This disc at predetermined points on one face thereof is provided with braking elements 33. On one face of the bearing 26, opposite the disc 3l, is fixed a disc 34 by means of tabs 35. This disc, like the disc 3!, at predetermined points is provided with braking elements 35.

The arrangement is such that when the stator is deenergized, the braking elements 33 of the disc 3| will engage the braking elements 36 of the disc 34, with the result that the rotor will be brought to a stop and prevented from overriding by its own inertia. Upon energization of the stator, the rotor will shift laterally within the magnetic field of the stator and thus project the driving gear 23 into meshing engagement with respect to the driven gear 13.

In Fig. 9 I have shown the same construction as that shown in Fig. 4, except in Fig. 9 the gear 23 remains in meshing engagement with the gear [3 during the braking action of the braking cams 33 and 36.

The simplicity of the construction of my invention will be obvious from the description herein. My invention. may be manufactured at an economical cost.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variationand modification without departing from the spirit of the invention. I, therefore-,do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come; within the scope of the appended claims.

Having thus described, my invention, what I claim as new and desire to protect by Letters Patent is:

1. An electric motor including a rotor and a stator, a shaft supporting the rotor for rotation with respect to the stator and for movement from a central position with respect to the stator, a stationary sleeve embracing one end of the shaft at one side of the rotor, a coil spring embracing said sleeve and yield'ably bearing on the rotor to move the rotor from said central position with respect to the stator upon deenergization of the latter, and a braking device comprising confronting brake discs, one carried by the rotor on the side thereof opposite the side of the rotor engaged by the spring and theother carried by the stator and effective to brake rotation of the rotor upon deenergization of the stator and projection of the rotor by said spring to a decentral position with respect to said stator.

2. An electric motor including a rotor and a stator, a shaft supporting the rotor for rotation with respect to the stator and for movement from acentral positionwith respect to the stator, a stationary sleeve embracing one end of the shaft at one side of the rotor, a coil spring embracing said sleeve and yieldably bearing on the rotor to move the rotor from said central position with respect to the stator upon deenergization of the latter, a braking: device comprising confronting brake di'scs,,one. carried by the rotor on the side thereof opposite the side of the rotor engaged by the spring: and. the. other carried by the stator and effective to brake rotation of the rotor upon deenergization of the stator and projection of the rotor by said spring to a decentral position with respect tosaid stator, and radially disposed laterally projecting braking elements on the confronting faces of said discs.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,501,497 Schwarz July 15, 1924 1,771,281 Wilsing July. 22, 1930 1,903,230 Stewart a- Mar. 28,1933 2,052,929- Kronmiller Sept. 1, 1936 2,172,440 Edmondson Sept. 12, 1-939 2445,6518 Bishofberger July 20, 1-948 

